Deep-sea litter in the Gulf of Cadiz (Northeastern Atlantic, Spain)

This study describes the distribution and composition of litter from the Gulf of Cadiz (Northeastern Atlantic, Spain), a region of confluence between the Atlantic and Mediterranean, with intense maritime traffic. Several geological features, such as canyons, open slopes and contourite furrows and channels, were surveyed by remotely operated vehicle (ROV) observations between depths of 220 and 1000 m. Marine litter was quantified by grouping the observations into six categories. Our results indicate the presence of markedly different habitats in which a complex collection of different types of litter accumulate in relation to bottom current flows and maritime and fishing routes. This result justifies a seascape approach in further anthropogenic impact studies within deep-sea areas.Postprint (author's final draft

Identificación de riesgos geoambientales y su valoración en la zona de hundimiento del buque Prestige

Potential geological hazard assessment has been carried out in the area where the Prestige vessel was sunk using a broad database that comprises: multibeam, high and ultra-high resolution seismic profiles, gravity cores, onland seismicity stations and Ocean Bottom Seismometers (OBS). The main results of this study indicate that among the geologic factors that can be considered as potential hazards, four main categories can be differentiated based on their origin: morphologic, sedimentary, tectonic, and seismicity. Hazards of morphologic origin include steep gradients; the morphologic features suggest the occurrence of mass-wasting instabilities. Hazards of sedimentary origin also includes the occurrence of slope instability processes in form of single slides and a great variety of erosive and depositional gravity flows (debris and turbidity flows). Hazards of tectonic and seismic origin are important because the sinking area straddles the Calida Bank which is a structural seamount with a moderate tectonic activity that results in a latent seismicity of low to moderate magnitude. The interaction of these factors leads to consider to the risk as medium, and the degree of exposure of the bow and stern as high. Several general and specific recommendations are made in order to increase the geological and geophysics knowledgement in the Prestige sinking area and Spanish continental margins and deep sea areas. These recommendations also should be used to elaborate the options for reducing the hazard and loss

Distribution, behaviour and litter interactions of deep-sea crustacean of the Gulf of Cadiz (NE Atlantic)

The deep-sea decapod crustacean assemblage of the Gulf of Cadiz is presently poorly characterized. Eighteen ROV video-transects (50 hours) were carried between 173 to 988 m depth on the continental slope. A total of 4339 individuals of 13 taxa were observed. Bathynectes maravigna (98 individuals and 2.3%), and Polybius henslowii (1691 individuals and 39.0%), were the most represented, followed by Munida sp. (1748 individuals, 40.2%). Individuals classified at family level were: Crangonidae (14 individuals, 0.3%), Majidae (1 individual, <0.1%), Paguridae (39 individuals, 0.9%), and Pandalidae (48 individuals, 1.1%). For a large group of animals, only a subclass or infraorder classification was achieved: Eumalacostraca (674 individuals, 15.5%) and Brachyura (2 individuals, <0.1%). Less observed specieswere: Nephrops norvegicus (8 individuals and 0.18%), Parapenaeus longirostris(8 individuals and 0.2%), Plesionika martia (16 individuals and 0.4%), Acanthephyra sp. (2 individuals and <0.1%). Munida sp. occurred in high-density patches in crinoid (Leptometra celtica) facies on the upper slope. P. henslowiiwas found in a contouritic channel. Species reaction to ROV footprint were aggressive (claws forward projectionand within burrow retraction) for Bathynectes maravigna, Munida sp., N. norvegicus, and P.henslowii(burrowingwas reported for the first time in this latter species, to our best knowledge). Species interaction with litter in B. maravigna, Munida sp., P. martia and Pandalidae was observed: individuals hiding under different kind of plastic andmetal artefacts.Postprint (published version